In the current mobile communication system, in order to provide better services to a user group, a Closed Subscriber Group (CSG) needs to be formed with multiple Radio Resource Management (RRM) entities (i.e., network entities, such as base stations or cells in various mobile communication systems, in responsible for managing radio resources and access of user devices in a radio access network) for the specific user group. For instance, all users in a company or a school form a CSG, for providing specific access services. As for a specific user group, it is ubiquitous that a CSG is formed with multiple RRM entities in the mobile communication system. In order to more clearly describe the situation, the description is given hereafter taking the Long Term Evolution (LTE) of the System Architecture Evolution (SAE) for example.
FIG. 1 illustrates a schematic diagram of the structure of a LTE system. As shown in FIG. 1, in the radio access network of the LTE system, the RRM entities include eNBs and Home eNBs (HeNBs). The radio access network may optionally include a HeNB GW. An eNB may directly connect with the Mobile Management Entity (MME) in the core network. When the radio access network includes the HeNB Gateway (GW), the HeNB needs to connect with the MME via a HeNB GW. When the network does not include the HeNB GW, the HeNB may directly connect with the MME.
As for the RRM entities in the LTE system, in order to provide more enriched access services, taking the HeNB for example, the conventional method provides several types including open, hybrid and CSG of the HeNB. The open-HeNB does not have a specific user group accessing the open-HeNB, and any UE may access the open-HeNB. The CSG-HeNB is a HeNB used by a user group formed by all the users in the company or the school mentioned above. The CSG-HeNB only permits the UEs in the specific user group served by the CSG-HeNB (For convenience of description, the UE in the specific user group is called the CSG UE) to access. The hybrid-HeNB not only forms a CSG with other HeNBs and permits the CSG UEs to access for convenience of providing better access services to the CSG UE, but also permits other non-CSG UEs (UEs which do not belong to this CSG) to access.
It can be seen from the above description that in the conventional mobile communication system, as for the RRM entities, the CSG is not only formed with multiple RRM entities to provide the CSG-RRM entity, such as the CSG-HeNB, and the hybrid-RMM entity, such as the hybrid-HeNB is also provided for providing more enriched access services. Meanwhile, the eNB may also support the CSG function, or is used as a hybrid-eNB while supporting the CSG function.
When the HeNB registers on the HeNB GW, the HeNB GW does not verify the HeNB, only the Safe Gateway (SeGW) verifies the HeNB. In this way, an attack HeNB may wiretap the information of the accessed UE using the ID of another HeNB. At present, there is no scheme on the network side to prevent this kind of HeNB attack. Therefore, the 3GPP puts forward a required for verifying the ID of the HeNB and the message of the accessed UE by the HeNB GW or the MME.
Especially, as for the UE accessing the HeNB via the S1 handover procedure, how to verify the message of the UE accessed to the HeNB is not solved.